Organizers of the rally, to be held from 4:30-6:30 p.m., are urging local supporters to "bring a brightly colored balaclava" -- or ski mask -- out of support for Nadezhda Tolokonnikova, Maria Alyokhina and Yekaterina Samutsevich.

The women -- aged 22, 24 and 30 -- were arrested in March after performing a "punk prayer" in opposition to Vladimir Putin, who was re-elected as Russia's president two weeks later. The have been jailed since their arrest.